Materials Literature
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Silicon nitride was formed by nitriding acid-leached and pyrolyzed rice husk in a nitrogen atmosphere. The nitridation kinetics of the pyrolyzed husk pellet over a temperature range of 1473−1723 K were studied by a thermal gravimetric analysis (TGA) technique. The effects of gas flow rate, pellet size, pellet-forming…
Cationic, phosphine-ligated Pt−Au cluster compounds, [Pt(AuPPh 3 ) 8 ](NO 3 ) 2 ( 1 ) and [(PPh 3 )Pt(AuPPh 3 ) 6 ](NO 3 ) 2 ( 2 ), have been immobilized on silica and alumina supports. Characterization of the supported clusters by 31 P MAS NMR, IR, and UV−visible spectroscopy and study by chemisorption and temperatur…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTA Facile Synthesis and the Polymerization of Macrocyclic 1,4-Phenylene Sulfide (PPS) OligomersYi-Feng Wang and Allan S. HayView Author Information Department of Chemistry, McGill University, Montreal, Quebec, Canada H3A 2K6 Cite thi…
Extended X-ray absorption fine structure (EXAFS) spectroscopy was used to investigate the effects of oxidation and reduction on supported noble metal clusters. After long-term exposure to laboratory air at room temperature, platinum clusters with an average diameter of approximately 7 Å inside the pores of BaKLTL zeol…
The compound (dabcoH(2))(2)Cl(3)[CuCl(3)(H(2)O)(2)].H(2)O, where dabco = 1,4-diazabicyclo[2.2.2]octane, has been synthesized, its structure has been determined by single-crystal structural analysis, and its properties have been investigated by powder and single-crystal EPR spectroscopy. The compound crystallizes in sp…
The oriented-gas approximation was examined at the molecular level by using an ab initio molecular orbital method in order to investigate its basic assumption: the additivity of hyperpolarizabilities between molecules. The additivity was examined in an interacting 2-methyl-4-nitroaniline (MNA) pair, the first-neighbor…
Polarized laser Raman and FTIR spectroscopies, as well as wide angle X-ray diffraction (WAXD), have been employed in order to investigate the distribution of molecular orientation in uniaxially drawn solution-cast films of well-characterized polyesters, bearing hexyl side chains, at different draw ratios. Both the sec…
The transport kinetics of methanol in PMMA have been studied over the temperature range 25−60 °C, using magnetic resonance imaging. It is shown that transport behavior changes from being relaxation controlled (Case II) at the lowest temperature to approaching Fickian behavior at the higher temperatures. It is also sho…
The C02-H20-MeC03 system C02-H20-MeC03 system equilibria kinetics of C02-H20-MeC03 system evolution precipitation treatments decarbonation iron and manganese removal neutralization conditioning using scale inhibitors studies of different scale inhibitors other scale prevention methods treatments involving complexants…
The preparation of the alpha-1 and alpha-2 isomers of the Wells-Dawson 17 tungsto derivatives by standard methods is accompanied by a significant proportion of the other isomer present as an impurity. In this study, the alpha-1 and alpha-2 isomers of [Zn(H(2)O)P(2)W(17)O(61)](8)(-) have been prepared in >98% purity by…
Lors du filage de fibres de cellulose par le procede Lyocell utilisant le melange d'oxyde de N-methylmorpholine et d'eau, la formation de la structure des fibres a ete etudiee. La forme du filament dans l'air apres la filiere a ete mesuree en meme temps que la croissance de la birefringence en utilisant un appareillag…
Photoexcitation of p -nitroaniline (PNA) and its N -alkyl derivatives results in the formation of triplet states with dipole moments considerably larger than that of the ground state, as monitored by time-resolved microwave conductivity (TRMC). The triplet state lifetime, τ T, is only 54 ns for PNA in benzene but incr…
Energy-transfer rate constants between two trivalent lanthanide ions have been determined at a short and fixed distance of ca. 4 Å, by using mixed dimers of tris(acetylacetonato)lanthanide complex, Ln(acac)3, formed in chloroform. The energy-transfer rate constants were obtained by measuring the luminescence decay con…
A recursive approach is used to evaluate the resulting molecular structure of a network-forming system composed of a mixture of bifunctional and monofunctional prepolymer chains reacting with a polyfunctional cross-linker (A f + B 2 + B 1 ). This system can be used to find formulations for model networks with pendant…
The complex [CuNiL][ClO4]2·H2O (SNi= 1) of a dinucleating macrocycle H2L, derived from the [2: 1 : 1] condensation of 2,6-diformyl-4-methylphenol, 1,2-diaminoethane and 1,4-diaminobutane, has been obtained. The efflorescent dimethylformamide (dmf) adduct [CuNiL][ClO4]2·H2O·2dmf crystallizes in the orthorhombic crystal…
The controlled functionalization of polystyrene using a process of metalation with a potassium superbase followed by reaction with electrophiles is described. The method is advantageous because metalation is extremely efficient, occurring rapidly even at room temperature, and the degree of functionalization can be con…
AISI types 304, 316 and 317 stainless steels (SS) containing various levels of nitrogen were evaluated for their pitting corrosion resistance in an acidic chloride medium containing 0.5M NaCl and 0.5M H2SO4. Potentiodynamic anodic polarisation were conducted at room temperature to determine the critical pitting potent…
E. coli dihydrodipicolinate reductase exhibits unusual nucleotide specificity, with NADH being kinetically twice as effective as NADPH as a reductant as evidenced by their relative V/K values. To investigate the nature of the interactions which determine this specificity, we performed isothermal titration calorimetry…
The dispersion and surface structure of molybdena supported on CeO2 have been studied by using XRD, XPS, LRS and FTIR spectroscopies. The samples were prepared by mixing MoO3 and CeO2 and by impregnating CeO2 with an aqueous solution of ammonium polymolybdate. The results indicate that the dispersion capacity of MoO3…
Parameters for the commercially available modeling package SYBYL have been developed for Gd(3+) complexes allowing these to be studied with molecular mechanics. With these parameters and a technique termed the "coordination scan", the coordination numbers of Gd(III) based complexes can be predicted, and thus the hydra…